1. Field of the Invention
The present invention relates to mixtures of catenate and cyclic siloxane oligomers of formula I and II ##STR2## where substituents R consist of both alkoxy groups and unsaturated organofunctional groups alone or together with different organofunctional groups and where not more than one unsaturated organofunctional group is attached to one silicon atom. The present invention also relates to a process for preparing mixtures of catenate and cyclic siloxane oligomers and to their use.
2. Discussion of the Background
Mixtures of catenate and cyclic siloxane oligomers are obtained, for example, by controlled hydrolysis or condensation of organofunctional alkoxysilanes. A particular problem when preparing multifunctional siloxane oligomers is the highly differing hydrolysis or condensation behavior of the individual organoalkoxy- or organochlorosilanes.
EP 0 760 372 discloses water-containing solutions of OH-- and acrylic functional organosilanes and organosiloxanes. In these organosiloxanes, hydrolysis is virtually complete.
EP 0 518 057 and DE 196 24 032 disclose mixtures of catenate and/or cyclic vinyl- and also alkyl-functional siloxane oligomers which also carry alkoxy groups. Such mixtures are employed, for example to hydrophobicize mineral surfaces and pulverulent materials, and as cross linking agents for thermoplastic polyolefins.